Experimental Assessment of Cardiac Function during Acute Rabbit Cardiac Allograft Rejection

Though heart transplantation has been established as a treatment for intractable heart failure in Europe and the U.S.A., there are few experimental reports on heart function during acute rejection. We investigated the left ventricular cardiac functions during acute rejection using rabbit heterotopic heart transplantation models. Cardiac transplantation was performed using the Ono-Lindsey method. The animals were bred for 1 day (D1 group, n=7), 3 days (D3 group, n=7), 5 days (D5 group, n=7) and 7days (D7 group, n=7) after the heart transplantation. The isolated hearts were removed the day they were scheduled to be put to death. These hearts were placed in a Langendorf reflux unit and subjected to a constant-pressure reflux (100cm H_2O) with a 37℃ modified Krebs-Henseleit solution. Isovolumic left ventricular functions such as left ventricular developed pressure(LVDP), peak +dP/dt, peak -dP/dt and left ventricular distensibility(LV distensibility) were measured. At the same time, coronary flow was measured. Histological findings were classified from grade 0 (G0) to grade 3 (G3) in accordance with the Billingham classification system. Non-transplanted heart functions were measured in the Langendorf reflux unit and used a control (D0 n=7). Though heart rates had a tendency to decrease with the lapse of time after transplantation, there was no significant difference in heart rates among the groups. There were significant differences in LVDP under balloon volume from 0 ml to 0.5 ml between D0 and D3, D0 and D5 and D0 and D7 groups (p<0.05), but LVDP did not show a significant difference between D0 and D1 groups. In the peak +dP/dt, no significant difference was observed between the D0 and D1 groups, but significant differences were observed between D0 and D3, D0 and D5 and D0 and D7 groups. Peak -dP/dt and LV distensibility indicting diastolic function decreased significantly with the time lapse after transplantation (p<0.05). Coronary flow significantly decreased (p<0.05). The higher the rejection intensity was, the more LVDP decreased under balloon volume from 0 ml to 0,5 ml, with significant differences (p<0.05). Peak +dP/dt showed significant differences between G0 and G3, and G2 and G3. Peak -dP/dt and LV distensibility showed significant differences only between G0 and G3. The relationship between the number of days after transplantation and left ventricular functions suggested that the diastolic function drops earlier than the systolic function.

異所性心移植

等容性心機能

拒絶反応

収縮機能

拡張機能